| CI | confidence interval |
| D | difference |
| EET | extrathyroidal ectopic thymic tissue; |
| ET | ectopic thymus; |
| FNAB | fine-needle aspiration biopsy |
| IET | intrathyroidal ectopic thymus; |
| PD | power Doppler; |
| PTC | papillary thyroid carcinoma; |
| R1 | researcher 1 |
| R2 | researcher 2 |
| SD | standard deviation |
| SE | strain elastography |
| SWE | shear wave elastography |
| SWS | shear wave stiffness |
| SWR | shear wave ratio |
| US | ultrasound |